brown, watson digit books first printing, first uk p/b edition
cover art by ed emshwiller (re-used from mmpb of "first on the moon" jeff sutton (ace 1958), q.v.)
cover price 2'6
160pp. including titles, indicia etc, end pp.
the prequel novella is ''clash by night'' astounding science fiction vol. xxxi #1, 3/1943 as by ''lawrence o'donnell''
collected in ''clash by night and other stories'' henry kuttner & c. l. moore (hamlyn paperbacks 1980), q.v.